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1/*
2 * Copyright (c) 2015 Qualcomm Atheros, Inc.
3 *
4 * Permission to use, copy, modify, and/or distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 */
16
17#include <linux/hw_random.h>
18#include <linux/kthread.h>
19
20#include "ath9k.h"
21#include "hw.h"
22#include "ar9003_phy.h"
23
24static int ath9k_rng_data_read(struct ath_softc *sc, u32 *buf, u32 buf_size)
25{
26 int i, j;
27 u32 v1, v2, rng_last = sc->rng_last;
28 struct ath_hw *ah = sc->sc_ah;
29
30 ath9k_ps_wakeup(sc);
31
32 REG_RMW_FIELD(ah, AR_PHY_TEST(ah), AR_PHY_TEST_BBB_OBS_SEL, 1);
33 REG_CLR_BIT(ah, AR_PHY_TEST(ah), AR_PHY_TEST_RX_OBS_SEL_BIT5);
34 REG_RMW_FIELD(ah, AR_PHY_TEST_CTL_STATUS(ah), AR_PHY_TEST_CTL_RX_OBS_SEL, 0);
35
36 for (i = 0, j = 0; i < buf_size; i++) {
37 v1 = REG_READ(ah, AR_PHY_TST_ADC) & 0xffff;
38 v2 = REG_READ(ah, AR_PHY_TST_ADC) & 0xffff;
39
40 /* wait for data ready */
41 if (v1 && v2 && rng_last != v1 && v1 != v2 && v1 != 0xffff &&
42 v2 != 0xffff)
43 buf[j++] = (v1 << 16) | v2;
44
45 rng_last = v2;
46 }
47
48 ath9k_ps_restore(sc);
49
50 sc->rng_last = rng_last;
51
52 return j << 2;
53}
54
55static u32 ath9k_rng_delay_get(u32 fail_stats)
56{
57 u32 delay;
58
59 if (fail_stats < 100)
60 delay = 10;
61 else if (fail_stats < 105)
62 delay = 1000;
63 else
64 delay = 10000;
65
66 return delay;
67}
68
69static int ath9k_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
70{
71 struct ath_softc *sc = container_of(rng, struct ath_softc, rng_ops);
72 u32 fail_stats = 0, word;
73 int bytes_read = 0;
74
75 for (;;) {
76 if (max & ~3UL)
77 bytes_read = ath9k_rng_data_read(sc, buf, max >> 2);
78 if ((max & 3UL) && ath9k_rng_data_read(sc, &word, 1)) {
79 memcpy(buf + bytes_read, &word, max & 3UL);
80 bytes_read += max & 3UL;
81 memzero_explicit(&word, sizeof(word));
82 }
83 if (!wait || !max || likely(bytes_read) || fail_stats > 110)
84 break;
85
86 if (hwrng_msleep(rng, ath9k_rng_delay_get(++fail_stats)))
87 break;
88 }
89
90 if (wait && !bytes_read && max)
91 bytes_read = -EIO;
92 return bytes_read;
93}
94
95void ath9k_rng_start(struct ath_softc *sc)
96{
97 static atomic_t serial = ATOMIC_INIT(0);
98 struct ath_hw *ah = sc->sc_ah;
99
100 if (sc->rng_ops.read)
101 return;
102
103 if (!AR_SREV_9300_20_OR_LATER(ah))
104 return;
105
106 snprintf(sc->rng_name, sizeof(sc->rng_name), "ath9k_%u",
107 (atomic_inc_return(&serial) - 1) & U16_MAX);
108 sc->rng_ops.name = sc->rng_name;
109 sc->rng_ops.read = ath9k_rng_read;
110 sc->rng_ops.quality = 320;
111
112 if (devm_hwrng_register(sc->dev, &sc->rng_ops))
113 sc->rng_ops.read = NULL;
114}
115
116void ath9k_rng_stop(struct ath_softc *sc)
117{
118 if (sc->rng_ops.read) {
119 devm_hwrng_unregister(sc->dev, &sc->rng_ops);
120 sc->rng_ops.read = NULL;
121 }
122}
1/*
2 * Copyright (c) 2015 Qualcomm Atheros, Inc.
3 *
4 * Permission to use, copy, modify, and/or distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 */
16
17#include <linux/hw_random.h>
18#include <linux/kthread.h>
19
20#include "ath9k.h"
21#include "hw.h"
22#include "ar9003_phy.h"
23
24#define ATH9K_RNG_BUF_SIZE 320
25#define ATH9K_RNG_ENTROPY(x) (((x) * 8 * 10) >> 5) /* quality: 10/32 */
26
27static DECLARE_WAIT_QUEUE_HEAD(rng_queue);
28
29static int ath9k_rng_data_read(struct ath_softc *sc, u32 *buf, u32 buf_size)
30{
31 int i, j;
32 u32 v1, v2, rng_last = sc->rng_last;
33 struct ath_hw *ah = sc->sc_ah;
34
35 ath9k_ps_wakeup(sc);
36
37 REG_RMW_FIELD(ah, AR_PHY_TEST, AR_PHY_TEST_BBB_OBS_SEL, 1);
38 REG_CLR_BIT(ah, AR_PHY_TEST, AR_PHY_TEST_RX_OBS_SEL_BIT5);
39 REG_RMW_FIELD(ah, AR_PHY_TEST_CTL_STATUS, AR_PHY_TEST_CTL_RX_OBS_SEL, 0);
40
41 for (i = 0, j = 0; i < buf_size; i++) {
42 v1 = REG_READ(ah, AR_PHY_TST_ADC) & 0xffff;
43 v2 = REG_READ(ah, AR_PHY_TST_ADC) & 0xffff;
44
45 /* wait for data ready */
46 if (v1 && v2 && rng_last != v1 && v1 != v2 && v1 != 0xffff &&
47 v2 != 0xffff)
48 buf[j++] = (v1 << 16) | v2;
49
50 rng_last = v2;
51 }
52
53 ath9k_ps_restore(sc);
54
55 sc->rng_last = rng_last;
56
57 return j << 2;
58}
59
60static u32 ath9k_rng_delay_get(u32 fail_stats)
61{
62 u32 delay;
63
64 if (fail_stats < 100)
65 delay = 10;
66 else if (fail_stats < 105)
67 delay = 1000;
68 else
69 delay = 10000;
70
71 return delay;
72}
73
74static int ath9k_rng_kthread(void *data)
75{
76 int bytes_read;
77 struct ath_softc *sc = data;
78 u32 *rng_buf;
79 u32 delay, fail_stats = 0;
80
81 rng_buf = kmalloc_array(ATH9K_RNG_BUF_SIZE, sizeof(u32), GFP_KERNEL);
82 if (!rng_buf)
83 goto out;
84
85 while (!kthread_should_stop()) {
86 bytes_read = ath9k_rng_data_read(sc, rng_buf,
87 ATH9K_RNG_BUF_SIZE);
88 if (unlikely(!bytes_read)) {
89 delay = ath9k_rng_delay_get(++fail_stats);
90 wait_event_interruptible_timeout(rng_queue,
91 kthread_should_stop(),
92 msecs_to_jiffies(delay));
93 continue;
94 }
95
96 fail_stats = 0;
97
98 /* sleep until entropy bits under write_wakeup_threshold */
99 add_hwgenerator_randomness((void *)rng_buf, bytes_read,
100 ATH9K_RNG_ENTROPY(bytes_read));
101 }
102
103 kfree(rng_buf);
104out:
105 sc->rng_task = NULL;
106
107 return 0;
108}
109
110void ath9k_rng_start(struct ath_softc *sc)
111{
112 struct ath_hw *ah = sc->sc_ah;
113
114 if (sc->rng_task)
115 return;
116
117 if (!AR_SREV_9300_20_OR_LATER(ah))
118 return;
119
120 sc->rng_task = kthread_run(ath9k_rng_kthread, sc, "ath9k-hwrng");
121 if (IS_ERR(sc->rng_task))
122 sc->rng_task = NULL;
123}
124
125void ath9k_rng_stop(struct ath_softc *sc)
126{
127 if (sc->rng_task) {
128 kthread_stop(sc->rng_task);
129 sc->rng_task = NULL;
130 }
131}